[KAFKA-10110] ConnectDistributed fails with NPE when Kafka cluster has no ID

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 2.6.0
• Fix Version/s: 2.6.0
• Component/s: connect
• Assignee: Randall Hauch
• Reporter: Randall Hauch
• Reviewer: Konstantine Karantasis
• Created: 05/Jun/20 15:01
• Updated: 05/Jun/20 20:54
• Resolved: 05/Jun/20 20:54

Description

When a Connect worker starts, recent changes from KIP-606 / KAFKA-9960 attempt to put the Kafka cluster ID into the new KafkaMetricsContext. But the Kafka cluster ID can be null, resulting in an NPE shown in the following log snippet:

[2020-06-04 15:01:02,900] INFO Kafka cluster ID: null (org.apache.kafka.connect.util.ConnectUtils)
...
[2020-06-04 15:01:03,271] ERROR Stopping due to error (org.apache.kafka.connect.cli.ConnectDistributed)
java.lang.NullPointerException
    at org.apache.kafka.common.metrics.KafkaMetricsContext.lambda$new$0(KafkaMetricsContext.java:48)
    at java.util.HashMap.forEach(HashMap.java:1289)
    at org.apache.kafka.common.metrics.KafkaMetricsContext.<init>(KafkaMetricsContext.java:48)
    at org.apache.kafka.connect.runtime.ConnectMetrics.<init>(ConnectMetrics.java:100)
    at org.apache.kafka.connect.runtime.Worker.<init>(Worker.java:135)
    at org.apache.kafka.connect.runtime.Worker.<init>(Worker.java:121)
    at org.apache.kafka.connect.cli.ConnectDistributed.startConnect(ConnectDistributed.java:111)
    at org.apache.kafka.connect.cli.ConnectDistributed.main(ConnectDistributed.java:78)

Issue Links

• links to: GitHub Pull Request #8811